This document aims to inform the discussion about switching off rarely-used and poorly maintained skins. Based on data from the Wikimedia Foundation database, our conclusion is that Chick, Standard, MySkin, Nostalgia, Simple and Modern are so rarely used as to only questionably justify support.[1]

The basic dataset we started with was a list of users grouped by skin choice, number of edits and activity levels.[2] The groups were:

Last active (months ago)

Edits

0-1

0

1-3

1-9

3-6

10-99

6-12

100-999

12+

1,000-9,999

N/A

10,000+

The relevant data was retrieved from each Wikimedia project, and, excluding "non-project" projects (the checkuser wiki, the board wiki, so on) merged into a single dataset, which was then analysed using this script.

One limitation of the data is that we could only retrieve users who had actively set a preference for their skin; users who had not done this displayed with a null value in the relevant table. Such users are not included in the numbers for Vector in the next section, which leads to an underrepresentation of Vector. Based on an approximate calculation,[3] this may exclude up to 85 per cent of users.

While this sounds bad, it's actually not that big of a problem. Users who have not explicitly set their skin are automatically exposed to the default skin, Vector. In other words, while this lack of data does throw the numbers off, they throw it off in a direction we don't care about: the results of the analysis are biased towards, rather than away from, the skins we're considering removing.

Based on the global dataset of user preferences, the use of skins for all accounts is:

Skin

Total number of accounts

Percentage

Chick

38,211

0.26%

Cologne Blue

98,541

0.68%

Modern

90,404

0.62%

Monobook

2,953,592

20.49%

MySkin

20,376

0.14%

Nostalgia

29,650

0.20%

Simple

18,218

0.12%

Standard

45,123

0.31%

Vector

11,116,612

77.14%

Skin usage stats for Wikimedia projects (power users only)

To summarise the impact of our changes, then; they will affect 151,578 accounts globally, or 1.05% of accounts. This doesn't tell the whole story on its own, however: most accounts overall are going to be inactive. If it turns out that only 1 per cent of accounts use to-be-deprecated skins, but they're 30 per cent of the active population, we have a problem.

In an attempt to gauge if this is an issue, the data was again analysed, but this time cut down to power users. For these purposes, we are looking at users who have:

Been active within the last 6 months; and

Have made over 1,000 edits, total, on their particular wiki.

Looking at that we get the following data, we see that any switch-off across all Wikimedia wikis would impact 397 power users (2.69%).